Fluid pressure mechanism



April 23, 1940. v R. s. SANFORD ET AL 2,198,129

FLUID PRESSURE MECHANISM Original Filed Jan. 23, 1936 INVENTORS P0 15. Sword BY W lz/JAndl-es ATTORNEY as PATENT OFFICE rwm rnsssuim MECHANISM Roy S. Sanford and William]. Andres, Pittsburgh, Pa., assignors to Bendix-Westinghouse Automotive Air Brake Company, Pittsburgh,

' UNITED STAT Pa., a corporation of Delaware Original application January 23, 1936, Serial No.

60,504. Divided and this application June 21,

1931, Serial No. 149,504

5 Claims.

This invention relates to piston structure and packing therefor, and more particularly to an improved type of construction suitable for use in connection with fluid pressure actuators.

Ill P t and ylinder arrangements for actulimits of the invention, reference being had for 5 ating various devices, as for example, the clutch that purpose to the appended claims. lever 01' brake lever of an automotive vehicle, it n the drawing, wherein similar reference charhas heretofore been proposed to position the cylacters refer to like parts throughout the several inder generally in a horizontal plane, and, due to views:

l the angular movement of the actuated lever con- Fig. 1 is an axial sectional view of a piston and no nected thereto, it has been necessary to concylinder arrangement constructed in accordance struct the parts in such manner as to permit of a, with the principles of the present invention, and slight lateral movement of the piston rod during Fig. 2 is a fragmentary view in perspective of its reciprocating movements. With such prior the piston cup of Fig. l.

constructions, however, due to the rocking of the In the illustrated embodiment of the invention, it

piston and the weight of the latter, it'has been the piston d y er arran m nt is c st found. that thepiston sealing cup is subject to tuted by a cylinder 3 provided with end walls t great wear at the bottom or the cylinder and in and 5. The end wall 4 has an open n 6 t e a relatively short space of time becomes disfor connection with any suitable-source of fluid s torted to such a degree that eiilcient sealing of the power for actuating the pi tonso actuating fluid supplied the cylinder is no longer "Within the cyl there is isp d a p sobtained. ton i which is of lesser diameter than the interior It is accordingly one of the objects of the preswall of the cylinder, the Said P n being ent invention to provide in a structure '01 the ur i a pi n ro which latter x n above character, a novel piston assembly which through a ar d p n 9 in the d wa l 5 shall be so constituted as to avoid these disad and is connected to any suitable type of device to vantages. be actuated, not shown. A flexible fluid-sealing Another object is to provide a piston assembly P n p "I v n a l yp d p which is capable of a limited degree of rocking ture H is maintained in position against the pisl in movement without causing excessive wearing of on 1 y means of a follower plate ii, the latter so the piston sealing cup. being threadedly received by the end of the pis- Still another object is to provide a novel fle'xiton rod 8 within the cylinder and forced tightly ble sealing cup for a piston which shall be prointo engagement with thefiuid-sealing cup. As vided with a metallic wearing surface in order will be clear from Fig. l, the cup in is provided is that the life of the cup will be greatly increased w h 'flanged portion l3, directedwtoward the over those heretofore used. a pressure side of the assembly an which is in Another object is to provide a sealing cup which fluid-sealing engagement with the interior of the shall be flexible in nature and while retaining cylinder 3 at all times, thus effectively sealing one the fluid-sealing characteristics of rubber and/or side of the piston assembly from. the other.

19 similar flexible composition materials yet have In instances where the p n rod 8 is 0 the characteristics of the long wearing ability or t d to actuat an sin la yva v metal cups. such as the clutch lever or .brake lever of an au- A further object is to so form a flexible compotomotive vehicle, the enlarged opening 9 permits sition sealing cupthat the wearing surface thereof the slight required lateral movement of the g of will be composed of metallic screen cloth and Elston rod 8 during reciprocation thereof in DD rubber or other similar material. site directions. It will benoted from Fig. 1 that A still iurther object is to provide a pisto and due to the fact that the diameter of piston l is cup assembly which shall be relatively simple in less than the internal diameter of cylinder 3, the construction as well as economical of manufacpis n T w e u of n me t at ll ime gs ture, and at the same time being capable of efilwith the wall of the cylinder. In order, therefore,

clent operation over along period of time.

Other objects andnovel features of the invention will appear more fully hereinafter from the following detailed description when taken in connection with the accompanying drawing illustrating a preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is employed for purposes of illustration only and is not designed as a definition of the to provide a suitable support for the piston, while at the same time materially decreasing the wear on the piston cup i0 and any liability of distortion of the later, the plate I! is provided with a spherical or rounded peripheral portion M which n maintains at all times a line contact with the interior wall of the cylinder. This is due to the fact that the peripheral portion of the plate is a within the limits of rocking movement of the piston. This portion I4 is positioned closely adjacent the flange I3 of the sealing cup I0 and thus enables the above referred to slight rocking movement of the piston assembly without undue distortion of the cup. In order to subject the flanged portion I3 of the piston cup to the actuating fluid for sealing purposes, the plate I2 is provided with a plurality of apertures l5.

In flexible sealing cups heretofore provided, considerable difficulty has been encountered in providing a cup which combines the characteristics of efficient fluid sealing with long life. Various rubber and rubber-like composition materials heretofore employed have been efficient as to sealing when initially installed but have necessitated frequent replacements due to wearing of the cup and consequent leakage. By the present invention, it is proposed to employ a metallic wearing member in the form of a metallic wire screen cloth l6 embedded in the exterior surface only of the sealing cup. Such metallic screen cloth may take the form of woven brass wire, for example, but it is understood that different types of metal may be employed in order to secure the wearing qualities contemplated.

Preferably, in forming. thecup I0, the metallic screen It is preformed into a shape conforming with the finished cup. Thereafter the screen is placed within a suitable mold and the rubber or otherlcomposition, in molten condition, is forced into the mold with such pressure that the interstices of the cloth are completely filledl with the composition. The resultant product is then vulcanized in a well known manner. As will be readily appreciated from an inspection of Fig. 2, the outer surface of the resultant structure presents a combined composition and metallic surface which is perfectly smooth. The use of the metallic cloth employed herein not only materially increases the life of the sealing cup without sacrificing the characteristics of flexibility and eflicient sealing but moreover decreases the friction between the cup and cylinder in which it operates.

While the invention has been described herein with considerable particularity, it will be understood that the same is not limited to the form shown but may take other forms as will be understood by those skilled in the art. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

This application is a division of our application filed January 23, 1936, Serial No. 60,504, entitled Fluid pressure .mechanism.

What is. claimed is:

1. A cylinder and piston construction comprising a cylinder having an end wall provided with an opening for fluid, a piston in said cylinder, said piston being of lesser diameter than the internal diameter of the cylinder and having a piston rod, 9. second end wall provided on said cylinder and having an enlarged opening through which said rod extends, a flexible piston cup having its peripheral portion in fluid-sealing engagement with the interior of said cylinder, a

follower plate having a peripheral portion adapted to maintain a line contact with the interior of the cylinder adjacent the peripheral portion of said cup and in a plane perpendicular to the axis of the cylinder during longitudinal and angular movement thereof in the cylinder, and means for securing said piston, cup and plate in rigid assembled relation on said piston rod.

2. A cylinder and piston construction comprising a cylinder having an end wall provided with an opening for fluid, a piston in said cylinder, said piston being of lesser diameter than the internal diameter of the cylinder and having a piston rod, a second end wall provided on said cylinder and having an enlarged opening through which said rod extends, a piston cup having its peripheral portion in fluid-sealing engagement with the interior of said cylinder, a follower plate having a spherical portion engaging the interior of the cylinder adjacent the peripheral portion of said cup and cooperating with said cylinder to support said piston rod, piston and cup for universal movement with respect to said cylinder, and means for securing said piston, cup and plate in rigid assembled relation 07". said'piston rod.

3. In combination, a cylinder having oppositely-disposed end walls, a piston in said cylinder, a fluid-sealing cup attached to said piston, a follower plate rigidly secured to said cup and piston and having an outer surface so constituted as to provide a line contact with the interior of said cylinder in a plane perpendicular to the axis thereof during angular and longitudinal displacement of said plate therein, said plate being formed with a plurality of apertures therein, one end wall being provided with an opening for fluid, and a piston rod secured tosaid piston, said second end wall being provided with an opening through which said rod extends, said opening permitting an appreciable degree of lateral movement of said rod with respect to said therein, said plate being rigidly secured to said piston rod. and maintaining said cup against said piston.

5. A fluid pressure device comprising a cylinder adapted to receive. a fluid, a piston therein of substantially lesser diameter than the bore of said cylinder, a piston rod secured to said piston and positioned for lateral movement with respect tosaid cylinder, a piston cup carried by said piston rod, and means comprising a plate having a spherical portion of a diameter substantially equal to that of the cylinder bore and in engagement with the surface thereof for supporting the piston for longitudinal movement therein and angular movement about the center of said spherical portion, said plate being rigidly secured to said piston rod and maintaining said cup against said piston.

Roy S. SANFORD. WILLIAM J. ANDRES. 

